U.S. Pat. Nos. 3,627,507, 3,819,353 and 3,846,512 teach the use of carbamoylphosphonates as plant growth regulants which are especially useful for controlling the growth of woody vegetation. There is, however, no direct mention that any of these compounds can control bindweed, nor is there any mention that the control of binweed can be done in a fashion that is not injurious to desirable crop plants. The control of bindweed is unexpected since it is a very difficult task and ordinarily requires the use of powerful herbicides, which would also tend to be quite injurious to desired crop plants such as tomatoes, etc.